When the pump chamber of the vacuum unit is in a vacuum state, the oil will return to the pump chamber due to the liquid level difference, gravity and pressure difference between the oil tank and the pump chamber. Let's know the preventive measures to prevent oil return of vacuum unit. 1. Separate the oil near the exhaust valve from other oil, and the oil level is only slightly higher than the partition wall. 2. Move the oil tank and exhaust valve of the vacuum unit to one side to reduce the oil level and reduce the oil volume. 3. The plane of the valve seat shall be flat and the valve plate shall be elastic. 4. The shaft seal and hydrostatic seal parts shall be firm and replaced in time. 5. Add a pipe at the oil hole to make the oil level only slightly higher than the oil inlet. 6. Set the check valve mechanism to automatically close the oil inlet when the pump stops. 7. Set the oil pump and auxiliary mechanism to cut off the oil circuit when the pump is stopped. 8. The pump port of the vacuum unit is equipped with an inflation valve. 9. Install the inlet container. When the oil volume of the vacuum unit is large enough, the oil will return to the air inlet pipe, resulting in high resistance and stress of the rotor and the rotor, high stress of the exhaust valve and difficult startup, affecting the service life of the parts and reducing the reliability of the pump. Therefore, try to avoid stopping the pump to return oil. Its principle is to cut off the oil circuit when stopping the pump, eliminate the negative pressure in the pump chamber, reduce the liquid level difference and reduce the oil return. The vacuum unit is mainly a vacuum pump, which uses a pair of blade rotors in the pump cavity to synchronously push back to make the gas move and extract air. Its structure and working principle are similar to roots blower, and its suction port is connected with the main pump of vacuum container or vacuum system. The rotor of the vacuum pump does not contact and does not need to be lubricated with oil. Rotor profile includes arc, involute and cycloid. Involute rotor pump has high volume utilization and easy machining accuracy, so the rotor profile is usually involute. Secondly, the mechanical vacuum unit with a pair of sole shaped rotors rotating synchronously at high speed can not extract air independently, and the front stage needs to be equipped with oil seal and water ring for direct exhaust.
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